Waveguides can be fabricated with polymers or inorganic materials using lithographic techniques wherein a mask is aligned and a photosensitive material is exposed. In such techniques, if several optical devices are to be coupled by a single mode waveguide, the location of the devices must be accurate to submicron tolerances.
For example, in one commonly used method for actively aligning VCSELs (vertical cavity surface emitting lasers) to fiber optics, a VCSEL chip is aligned to a waveguide while monitoring the output of the waveguide. More than half of a typical photonic module assembly cost is incurred during such active alignment processes.
It would therefore be desirable to have a capability for adapting a waveguide to device locations and thereby relaxing the positioning tolerances of device locations during manufacturing. It would additionally be useful to have a less expensive fabrication technique which permits a VCSEL chip and detectors to be fixed in position prior to alignment.